Friday, November 30, 2007

I've been working right through the night for the IFL post-publication deadline, trying to get benchmarks for most of the imaginary nofib suite using Supero. It's now almost 9am, and I'm off to work once more, so here are the final raw results I'm going to be using in the IFL paper.

For these numbers, lower is better. The fastest optimiser gets a 1.00, all the others are scaled relative to it. The most red value is the slowest. ghc2 is GHC 6.8.1 with -O2. supero-* is running through the Yhc front end, then through Supero, then through GHC 6.8.1 -O2. none corresponds to the supero optimiser doing no inlining or optimisation, essentially giving GHC the whole program in one go. The other supero-* results are all based on Positive Supercompilation with homeomorphic embedding as the termination criteria and a given generalisation function. whistle is no generalisation criteria, msg is the most specific generalisation, and general is my newly created generalisation function. All the details will be in the paper I'm submitting later today.

I know some places where these results have fallen a bit flat of what they should, but even so, I'm very happy with this!

Sunday, November 25, 2007

After writing a VBA Macro to convert a PowerPoint with animation into a flat PowerPoint without animation (suitable for conversion to PDF), I wrote my talk. After writing my talk I realised I not only needed elements to appear on a click, but also disappear and reappear. Unfortunately my original macro script did not do that, so I've updated it with two new features:

Safer

The original code removed all slides which were not hidden to return to the previous state. Unfortunately, if you haven't yet run the AddElements script, that results in it deleting all your slides! Undo saves the day, but it would be nicer for RemElements to be a bit more considerate. This version tags all the slides it creates, then RemElements simply removes those with the appropriate tag - hopefully this removes the obvious "Doh!" moment from this tool.

Works with show/hide/reshow

The original code used the Shape.AnimationSettings properties to detect what happened to objects. Unfortunately, this property only records the first action associated with an object - I suspect in the past PowerPoint only allowed one action and this is merely here for compatibility. To get the full range of events you need to use the Slide.TimeLine property. Writing the code I ran into two issues: (1) objects with silly names; (2) mutability.

Objects With Silly Names

Some objects have properties which don't do what you might think! Effect.EffectType = msoAnimEffectAppear implies that the animation is to appear, but if Effect.Exit = msoTrue then this is the disappear effect! I was confused by this one for quite a while.

In order to solve all the naming problems, I made extensive use of the Visual Basic debugger included with Office, which puts many other debuggers to shame. It is at least 1000x better than any Haskell debugger I've ever seen, and equally far ahead of things like GDB. Microsoft's software may be maligned, but their debuggers are truly fantastic! It really does allow an entirely new style of development, and is particularly suited to dipping into a new API without having a large learning curve.

Mutability

Mutability is a bad idea. If you delete a shape, while you are iterating over a collection of shapes, you silently skip the element that comes after the deleted shape! If you delete a shape, and that shape is the subject of a transition, then that corresponding transition is deleted. If you change the Shape.AnimationSettings.Animate to msoFalse, this removes any associated transitions. All this means that to try and iterate over something starts to become a challenge!

The problem with mutability in this particular task is that it is unclear what is changing and when, leading to subtle bugs and lots of debugging. Again, the debugger helped, but not as much as before - having to single-step through quite deep properties is not a particularly fun task.

The Code

And here is the code, to be use as in the same way to the previous post.

'is the shape on this slide visible at point this time step (1..n)Function IsVisible(s As Slide, h As Shape, i As Integer) As Boolean

'first search for a start stateDim e As EffectIsVisible = TrueFor Each e In s.TimeLine.MainSequence If e.Shape Is h Then IsVisible = Not (e.Exit = msoFalse) Exit For End IfNext

'now run forward animating itDim n As Integer: n = 1For Each e In s.TimeLine.MainSequence If e.Timing.TriggerType = msoAnimTriggerOnPageClick Then n = n + 1 If n > i Then Exit For If e.Shape Is h Then IsVisible = (e.Exit = msoFalse)NextEnd Function

'How many animation steps are there'1 for a slide with no additional elementsFunction AnimationElements(s As Slide) As IntegerAnimationElements = 1Dim e As EffectFor Each e In s.TimeLine.MainSequence If e.Timing.TriggerType = msoAnimTriggerOnPageClick Then AnimationElements = AnimationElements + 1 End IfNextEnd Function

Saturday, November 24, 2007

I like to write talks in PowerPoint, because it has a nice interface and is a lot faster to work with for diagrams than Latex. I hope one day to move to using Google's online presentation creation tool, but there is one crucial feature missing that stops me - creating PDF's. If I am going to a place away from York, to present on another persons machine, the format I can guarantee that will display correctly is PDF.

Until now I've never written PowerPoint slides with "custom animations". A custom animation is something as simple as a slide where additional elements become visible with each click, like a pop-out box appearing or a circle around some relevant part of the slide. While its usually sufficient to get away without this feature, it is sometimes very handy. The reason I've stayed away is because of the conversion to PDF.

When Latex creates a slide with many sub-elements which appear at different stages, it creates multiple pages in the PDF. However, when using either OpenOffice's PDF converter or the Acrobat converter all the sub-elements are placed on one slide and are visible at all times - loosing the entire point of hiding elements!

I looked around the web for a tool to solve this problem, without success. I found one tool that seemed like it might help, but appeared to rely on having Acrobat Creator installed locally. I write my presentations on my machine, then remote desktop to the University machines to do the PDF conversion, and on those machines I don't have admin access. In addition, this tool required money to use, and may still not have worked.

Instead I wrote some VBA code, which deconstructs the slides with animations into multiple slides, then puts them back together after. The two macro's are called AddElements and RemElements. The code to AddElements cycles through each slide, duplicating it once for each level of clicky-ness in the animation, deleting the elements that shouldn't be visible yet, and hiding the original.

To run the code go to Tools/Macro/Visual Basic Editor, copy and paste the code into a project, then go to Tools/Macro/Run Macro and run AddElements. You can then use Acrobat to create a standard PDF, and after you are finished, run RemElements to put the project back to the way it was. Like all code you find on the net, please backup your presentation before you start - no warranties are offered or implied!

Dim max As Integer: max = 0 For Each shp In s.Shapes If shp.AnimationSettings.Animate = msoTrue Then If shp.AnimationSettings.AnimationOrder > max Then max = shp.AnimationSettings.AnimationOrder End If End If Next

Dim i2 As Integer For i2 = s2.Shapes.Count To 1 Step -1 With s2.Shapes(i2) If .AnimationSettings.Animate = msoTrue Then If .AnimationSettings.AnimationOrder > k Then .Delete Else .AnimationSettings.Animate = msoFalse End If End If End With Next NextNextEnd Sub